Since May 1993, faster versions of the LINKAGE software package enhanced by the principal investigator and students at Rice University have been freely available to the genetics research community. The new programs, nicknamed FASTLINK, are generally at least one order of magnitude faster than LINKAGE 5.1 on long runs. Version 2.0 of the investigator's code augmented the two FASTLINK programs that needed it with a checkpointing facility, so that if the underlying computer crashes during a run, the run can be restarted. In this proposal, the investigator seeks funding to: 1) Support research that will speed up the programs even more. 2) Support active maintenance of FASTLINK to get it to the point where it needs minimal maintenance. 3) Support the enhancement and conversion of experimental parallel implementations the investigator has done into versions that can be distributed to the user community.